Vacuum tank



pril 7, 1931. w. H. SCHUL-1E VACUUM TANK Filed May 24, 1929 as zgorfaeys.

Ms@ I Patented Apr. 7, 1931 UNITED STATES PATENT OFFICE WILLIAM H. SCHULZE, F CHICAGO, ILLINOIS, ASSIGNOR TO STEWART-WARNER COB- PORATION, OF CHICAGO, ILLINOIS, A CORPORATION 0F VIRGINIA 'VACUUM TANK Application led Hay 24, 1929. Serial No. 365,630.

The purpose of this invention is to provide a fuel lifting apparatus for supplying an internal combustion engine of a type commonly called a vacuum tank, in which the usual suction controlling valve may be omitted without reducing the pumping or fuel lifting capacity of a tank of a given size, and in which the air admitted for overcoming the suction so as to permit the vacuum chamber to discharge the lifted liquid into the reserve chamber ready for supplying the carbureter, shall be taken directly from the reserve chamber where it is in contact with the gasoline, so that it is more or less impregnated with the fuel vapor and thereb somewhat less liable to disturb the fuel mixture proportions when it passes through the suction connection into the engine intake manifold. The invention con-4 sists in the elements and features of constructon shown and described as indicated in the claims.

In the drawings:

Figure 1 is a vertical section of a vacuum tankembodying one form of this invention.

Figure 2 is a top plan view of the same.

In the drawings the vacuum chamber is indicated in entirety at A. The outer body member which comprises the reserve chamber is indicated at B. The two members, A and B, are secured together and closed at the top,

. except as to connections hereinafter mentioned, by a cap plate, C, which serves the purpose of securing the two members together by being marginally lapped above the lapped fianges, a and b, of the members, A and B,

and secured by bolts, 10, with suitable packing gaskets, 11 and 12, interposed between the lapped flanges to render the vacuum chamber liquid tight. At a convenient point in the 4o circumference of the lap ed cap and chamber fianges there is mounte in registered apertures in the flanges, a nipple, 30, which serves as the atmosphere vent or inlet for the reserve chamber.

The fuel inlet connection is seen at D, dischargingthrough the ca plate in which the fitting, D, is mounted. uction connection is seen at E, this fitting, also mounted in the cap plate, having very closely restricted suction port, as seen at e.

A tubular fitting, F, open freely at the upper end and having at the lower end a port and valve seat, f, is mounted by its lower end in the bottom of the vacuum chamber member,

A, and constitutes an air inlet from the reserve chamber, B, by which the air derived through the atmosphere vent port nipple, 30, is admitted to the upper part of the vacuum chamber. At a position directly over the upper open end of the tubular fitting, F, there is mounted in the cap, E, a short fitting, G, of inverted cup form, having an opening, 15, in the upper end, and freely open to its full tubular diameter at the lower end.

Said fitting serves as a piston cylinder and is fitted with a piston member, G1, which is carried at the upper end of the stem, 40, which at its lowerl end carries a valve, 50, dimensioned and arranged for seating downward 1y at the port and valve seat, f, when the piston, G1, is retracted downwardly in the cylinder, G. A spider, 4l, may be provided mounted at the under side of the bottom of the vacuum chamber for affording guidance to the valve stem, 40, as seen at 42.

At any convenient point in the area of the bottom of the vacuum chamber, a fuel outlet fitting, H, is mounted extending down in the reserve chamber and having an outlet valve h, arranged to be held seated by the suction in the vacuum chamber, and to open for discharge of fuel by gravity when the suction is released by the opening of the valve, 50, for admitting atmospheric pressure to the vacuum chamber adequately for that purose.

P Within the vacuum chamber there is mounted on and guided for up and down movement, a float, K, which is connected with the valve-andpiston stem, 40, for opening the valve, 50, when the float is lifted by the risev of the liquid in the chamber to a predetermined height, and closing the valve when the lfloat is lowered by the subsidance of the liquid to a predetermined low level.

As illustrated, the tubular fittlng F, serves most conveniently for guidance of .the oat which is centrally apertured for being thus mounted and guided on said fittin And a oke k, secured to the upper end o the oat, lilas at the middle a short sleeve or hub, 47 by which the yoke is engaged with the stem, 40, sliding between upper and lower stops, 44 and 45, on the stem, 40.

Said hub, 47 has an encompassing groove, 48, in which the proximate ends of snap action springs, 49, 49, are seated, said springs having their remote ends pivotally engaged with lugs, 46, 46, on the under side ofthe cap plate, C, and being formed for resllient extension to a length substantially greater than the radial distance between said hub, 47, and the lugs, 46, 46, respectively, the springs beinv' thus adapted to react for snapping the hu up or down from a position in radial alignment with the pivotal engagement of the snap action springs with the lugs.

Upon considering this structure it may be understood that the intended operation is,that

. as a vacuum chamber becomes filled with liquid lifted into it by suction while the valve, 50, is held closed by the reaction of the snap action springs at the position seen in Figure 1, the float, at some predetermined high level of the liquid, will be submerged to a suiiicient distance to make its buoyant value exceed the resilient reaction of the lsnap action springs, and force the hub collar, 47, upward along the stem toward the upper stop, 44; and the parts are dimensioned -so that in y this movement the snap action springs pass the position of alignment with each other before the hub collar reaches the upper stop, 44, on the stem; and the springs passing this aligned position, reacting upwardly, add the force of their resiliency to the buoyant value ovf the float due to its submergence, and cause the hub collar, 47, which immediately encounters the upper stop to lift thc valve, 50, to open position.

It will be understood that in this operation the areas of the valve, 50, and piston, G1, being substantially equal, the suction action on the valve tending to open it is counterbalanced by the suction action on the piston tending to move it and the valve, 50, in opposite dlrections; and that accordingly, the

force tending to hold the valve seated, and which must be overcome by any means which will open it, is the force exerted by the snap action springs in their initial positions seen in Figure 1, trending downwardly from aligned position, plus the friction of the parts, including the friction of the piston in the piston chamber. And it may be further understood that the snap action springs need only be stifl:` enough to render their resilient reaction sufficient to ensure against the vent valve being jarrcd off its seat by the vibration of the engine or the jolting bf the vehicle.

And it will be understood, therefore, that the float, K, need only be large enough to render its buoyant value due to its submergence beyond the plane at which its weight and buoyancy are at balance, equal to the slight force necessary to keep the valve from being jarred open.

It may be understood, therefore, that a tank of this construction will have fuel feeding capacity much greater for given dimensions than one in which the float must have a buoyant value for breaking the suction hold on the valve to be open by it, due to the maximum vacuum required to be developed in the chamber for effecting the maximum required fuel lift, as is the case in vacuum tanks of familiar construction in common use.

Upon like consideration of the construction and its operation\as above described, it may be noted that in order that the range between the predetermined high level at which the valve, 50, is opened by the float, and the predetermined low level, may be as great as possible and comprise as nearly as possible the full fuel capacity of the chamber, the {ioat is desirably made as shown, relatively long and slender, so that the distance from the balance plane to the oint of complete submersion for giving uoyant value for relieving the snap springs and operating the' valve, shall be as great as pos sible, and the distance from said balance plane to the point of complete emergence of the float for rendering its unsubmerged Weight adequate for reversing the snap action and closing the valve shall also be as great as possible; and this consideration determines the dimensions of the arts, as shown, with the float a relatively thin hollow cylinder.

It will bc recognized that the piston' operating in the cylinder is substantially an element of the wall of the vacuum chamber exposed exteriorly to atmospheric pressure and interiorly to the suction, and'movable inwardly and outwardly without opening the wall, being distinguished from a valve by the last mentioned circumstance. And this clement of the structure is accordingly thus defined in the claims; and I wish it to be understood that I do not limit myself to the specific form of such movable wall member which consists of a piston reciprocating in a piston chamber, but on the contrary, any form of wall member movable inwardly and outwardly without moving the wall may be employed without departing from this invention.

1. An apparatus for lifting fuel for serving an internal combustion engine com rising a vacuum chamber having a fuel inlet connection and havin at the upper part a suction connection an at the lower part a valve controlled liquid outlet; a duct leading from the upper part of the chamber to a port at the lower part, a valve controlling said port, the chamber having at the upper part al wall member which is movable inwardly and outwardly without opening the wall; operating connectionsl between said wall member and said valve extending through said duct arranged for communicating seating movement to the valve from the inward movement of the wall member due to vacuum in the chamber; other opera-tin connections for opening and closin sai valve, and means' for actuating sai other connections controlled by the level of the liquid in the chamber.

2. An apparatus for lifting fuel for serving an internal combustion engine com rising in combination a vacuum chamber aving a fuel inlet and having at the upper part a suction connection and at the lower part a valve controlled fuel outlet, an air inlet at the lower part of the chamber and a duct leading therefrom to the upper part of the chamber and constitutin the sole communication from said port'wit the interior of the chamber; a chamber wall comprising at the upper part a movable member arranged for inward and outward movement without opening the wall, a valve controlling the air inlet, and connection from the valve to the moving wall member extending through said duct, a {ioat in the chamber operatively associated with the valve stem for operating the valve for opening and closing the valve at predetermined high and low limits of the movement of the float due to change of liquid level in the chamber, the valve and movable wall member being relatively dimensioned for approximately counterbalancing each other in respect to the action of suction, and a spring snap action interposed between the iloat and the valve for adding the reaction of its spring element to the counterhalanced stress for opening the valve at the high level of the ioat and to the opposite counterbalance stress for closing the valve at the lower level thereof.

3. An apparatus for lifting fuel for serving an internal combustion engine comprising in combination a vacuum chamber having a fuel inlet and having at the upper part a suction connection and a wall member which is movable inwardly and outwardly without opening the wall, the chamber having at the lower part an air inlet and a duct leading therefrom extending upwardly inthe chamber and constituting the sole communication from said port to the interior of the chamber, a valve seating at said port having'its stem'extending up through-the duct and operatively connected with said movable wall member, a float in the chamber mounted slidingly on the valve stem, the latter having upper and lower stops for limiting said sliding movement and affording encounter for the float to operate the valve at the limits of said sliding movement, anda spring snap action device connected with the iioat for actuating the stem at the limits of the sliding movement of the float for opening and closing the valve at the high and low limits respectively.

4. An apparatus for lifting fuel for serving an internal combustion engine comprising in combination a vacuum chamber having a fuel inlet and having at its upper part a suction connection, and a piston chamber and piston therein exposed exteriorly to atmosphere pressure and interiorly to sub-atmospheric pressure, the chamber having at the lower part an air inlet and a duct leading therefrom extending upwardly in the chamber and constituting the sole communication from said port to the. interior of the chamber, a valve seating atl said ort havin its stem extending up through t e duct an operatively connected with said movable wall member, a float in the chamber mounted slidingly on the valve stem, the latter havin upper and lower stops for limiting sai sliding movement and adording encounter for the iioat to operate the valve at the limits of said sliding movement, and a spring snap action connected with the float for actuating the stem at the limits of the sliding movement of the ioat for opening and closing the valve at the high and low limits respectively.

5. An apparatus for lifting fuel for supplying an internal combustion engine comprising a vacuum chamber having a fuel inlet connection and having at the upper part a suction connection and at the lower part a port for access ofatmos heric pressure, and an inwardly opening va ve controlling said port, said vacuum chamber having at its upper part an auxiliary variable capacity chamber having a movable wall member by whose movement the chamber capacity is increased and reduced, said movable wall member being exposed exteriorly to atmosphere pressure and interiorly to sub-.atmospheric pressure; operating connections between said valve and movable wall member arranged for opposing to each other the inward stresses on the valve and movable wall member respectively due to the vacuum in the chamber, other independently operating mechanical connections with sald valve for opening and closing the latter, and means for actuating said mechanical connections controlled by the level of the liquid in the chamber.

6. In the construction defined in claim 3, the movable wall member being at the top of the chamber and the valve being directly below it at thebottom of the chamber.

7. In the construction defined in claim 1,

the level-controlled means for actuating the 5 valve-opening-and-closing means comprising a fioat. having its vertlcal dimension very large relativel to its horizontal cross-sectional area, an the operating connections actuated by said oat being arranged for relatively small movement in opening and closin the valve.

n testimony whereof, I have hereunto set my hand at Chicago, Illinois, this 10th day of May,1929. i WILLIAM H. SCHULZE. 

